Miniature antenna

Abstract

A miniature antenna includes a feed-in element, a grounding element, a short circuit element and a radiating element. The grounding element includes a feed-in end portion and a link portion connected with the feed-in end portion. The feed-in end portion includes a feed-in point provided for feed-in of a radio frequency signal. The grounding element is spaced apart from the feed-in element and is disposed adjacent to the feed-in point. The short circuit element extends from the link portion to the grounding element, and substantially surrounds the feed-in end portion. The radiating element extends from the link portion, and substantially surrounds the short circuit element.

What is claimed is: 
     
         1 . A miniature antenna comprising:
 a feed-in element which includes a feed-in end portion and a link portion connected electrically with said feed-in end portion, said feed-in end portion including a feed-in point provided for feed-in of a radio frequency signal;   a grounding element spaced apart from said feed-in element and disposed adjacent to said feed-in point;   a short circuit element extending from said link portion to said grounding element, and substantially surrounding said feed-in end portion; and   a first radiating element extending from said link portion and substantially surrounding said short circuit element.   
     
     
         2 . The miniature antenna as claimed in  claim 1 , wherein said first radiating element includes:
 a first radiating section extending substantially as an arc from said link portion toward said grounding element to substantially surround said short circuit element;   a connecting section connected to said first radiating section, and extending away from said feed-in end portion; and   a second radiating section extending substantially as an arc from said connecting section and away from said grounding element to be disposed outwardly of said first radiating section;   wherein one of said first and second radiating sections extends in a clockwise direction, and the other one of said first and second radiating sections extends in a counterclockwise direction.   
     
     
         3 . The miniature antenna as claimed in  claim 2 , wherein said first radiating section extends substantially as a 270-degree circular arc. 
     
     
         4 . The miniature antenna as claimed in  claim 2 , wherein said second radiating section extends substantially as a 150-degree circular arc. 
     
     
         5 . The miniature antenna as claimed in  claim 1 , wherein said short circuit element is substantially arc-shaped. 
     
     
         6 . The miniature antenna as claimed in  claim 5 , wherein said short circuit element extends substantially as a 270-degree circular arc. 
     
     
         7 . The miniature antenna as claimed in  claim 1 , wherein said grounding element has one edge which is adjacent to said link portion and which is spaced apart from and parallel to said link portion. 
     
     
         8 . The miniature antenna as claimed in  claim 1 , further comprising a second radiating element which extends from said link portion, wherein said first radiating element and said second radiating element resonate in a first frequency band and a second frequency band, respectively. 
     
     
         9 . The miniature antenna as claimed in  claim 8 , wherein an overall length of said short circuit element and said first radiating element is substantially a quarter of a wavelength corresponding to the first frequency band. 
     
     
         10 . The miniature antenna as claimed in  claim 9 , wherein said second radiating element includes:
 a first radiating segment extending from said link portion and away from said feed-in element and said grounding element, and   a second radiating segment connected electrically with said first radiating segment and being substantially perpendicular to said first radiating segment.   
     
     
         11 . The miniature antenna as claimed in  claim 8 , further comprising:
 a substrate which has a first surface and a second surface opposite to said first surface, said feed-in element, said grounding element, said short circuit element, said first radiating element and said second radiating element being disposed on said first surface; and   a subminiature connector which includes a conductive tube, a conductive frame disposed at one end of said conductive tube, a plurality of conductive pillars extending from said conductive frame and away from said conductive tube, a conductive core disposed inside said conductive tube in a non-contacting manner, and an insulator disposed between said conductive tube and said conductive core;   wherein one end of each of said conductive pillars distal from said conductive frame is disposed at said substrate, one of said conductive pillars penetrates through said substrate and is connected electrically with said grounding element, one end of said conductive core penetrates through said substrate and is connected electrically with said feed-in point, and said conductive core is used for transmission of the radio frequency signal to said feed-in point.   
     
     
         12 . The miniature antenna as claimed in  claim 11 , wherein said substrate is spaced apart from said conductive frame by approximately 3 mm. 
     
     
         13 . The miniature antenna as claimed in  claim 8 , wherein the first frequency band substantially ranges from 2.4 GHz to 2.5 GHz. 
     
     
         14 . The miniature antenna as claimed in  claim 8 , wherein the second frequency band substantially ranges from 5.1 GHz to 5.8 GHz.